Surface mount component

ABSTRACT

An apparatus including a substrate, and a surface mount component coupled with a top surface of the substrate, where the component includes side surfaces and a bottom surface, and the bottom surface is disposed adjacent to the top surface of the substrate. The side surfaces and the bottom surface of the surface mount component define a lower portion therebetween, the lower portion recessed away from the bottom component surface to allow solder to flow freely around a mounting lead of the surface mount component, for example, during the reflow process.

TECHNICAL FIELD

[0001] The present invention relates generally to connectors, and inparticular relates to surface mount connectors methods of attachmenttherefor.

BACKGROUND

[0002] Circuit boards are designed to have more power with increasingcapabilities, and simultaneously being designed to achieve more usingless space, at faster speeds, without substantially adding to theoverall cost of the product. As a result, more chips, as well as othertypes of components, are being surface mounted to the printed circuitboard, resulting in a higher component density within a smaller volumeof space. However, conventional surface mount processing and methods aresometimes incapable of adequately providing a reliable high densitysurface mountable component, such as a connector. Furthermore,conventional surface mount processing is sometimes incapable ofadequately providing a reliable surface mount component which can handleforces applied to printed circuit boards in standard processes, such asassembly, testing and/or shipping, and in the user field,post-production.

[0003] One example of the kinds of forces applied to the surface mountcomponents is during assembly of the printed circuit board. In toughhandling processes, such as shipping and/or testing, which placeadditional stresses on the circuit board and/or the surface mountcomponents, the risk of mechanical and/or electrical failure of thesesurface mount components is increased. Furthermore, similar or otherconditions in the user field could result in failure.

[0004] One example of a component which is surface mounted on to theprinted circuit board is a surface mount RJ45 connector. In current RJ45connectors, the plastic body 50 of the connector is substantiallysquare-shaped at a juncture near the lead 52, the printed circuit board54, and a lower edge 56 of the plastic body 50, as shown in FIG. 1. Thesquare shape is disposed directly adjacent to the lead 52 and theprinted circuit board 54. When solder is flowed around the leads 52 ofthe component, the solder flow is obstructed during the reflow process,and a high concentration of stress results in the encircled area 60 ofthe fillet 66. Furthermore, mounting pegs 64 are disposed through theprinted circuit board 54, and a distal end 62 of the mounting pegs 64protrudes out of the printed circuit board 54. As the printed circuitboard is placed on planar surfaces, such as during testing, furtherstress is placed on the fillet 66, occasionally causing the fillet 66 tocrack. The solder joints at the leads have a marginal tensile strength,and are prone to developing mechanical fractures at this same location,leading to mechanical and/or electrical failure.

[0005] Accordingly, what is needed is a surface mount component that canbe better secured to the printed circuit board. What is further neededis a method of attaching a surface mount component that is bettersecured to the printed circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a cross-sectional view of a portion of a prior artsurface mount component.

[0007]FIG. 2 is a cross-sectional view of a portion of a surface mountcomponent as constructed in accordance with one embodiment.

[0008]FIG. 3 is a cross-sectional view of a portion of a surface mountcomponent as constructed in accordance with one embodiment.

[0009]FIG. 4A is a side view of a surface mount component as constructedin accordance with one embodiment.

[0010]FIG. 4B is a cross-sectional view of a surface mount component asconstructed in accordance with one embodiment.

[0011]FIG. 5A is a side view of a surface mount component as constructedin accordance with one embodiment.

[0012]FIG. 5B is a cross-sectional view of a surface mount component asconstructed in accordance with one embodiment.

[0013]FIG. 6 is a block diagram of a method for attaching a surfacemount component to a substrate as constructed in accordance with oneembodiment.

DETAILED DESCRIPTION

[0014] In the following detailed description of the preferredembodiments, reference is made to the accompanying drawings which form apart hereof, and in which is shown by way of illustration specificpreferred embodiments in which the inventions may be practiced. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention, and it is to be understood thatother embodiments may be utilized and that logical, mechanical andelectrical changes may be made without departing from the scope of thepresent inventions. The following detailed description is, therefore,not to be taken in a limiting sense, and the scope of the presentinvention is defined only by the appended claims.

[0015] A portion of a surface mount component 100 is illustrated inFIGS. 2-4 which allows for improved attachment to a substrate, andincreased resistance to mechanical and/or electrical continuity failure.The surface mount component 100 is mounted to a substrate 102, forinstance, a printed circuit board or a NIC (Network Interface Card)card. The substrate 102 includes a first top surface 104, a second lowersurface 106, and has one or more mounting holes 108 (FIG. 4) therein,where the mounting holes 108 (FIG. 4) extend fully or partially from thefirst top surface 104 to the second lower surface 106. In one option,the one or more mounting holes 108 (FIG. 4) comprise a through-hole inthe substrate 102. Examples of the surface mount component 100 include,but are not limited to, connectors such as FCI connectors or MolexConnectors. In one example, the surface mount component comprises asurface mount RJ-45 connector.

[0016] Referring to FIG. 2, a cross section of a connector 110 is shown.The connector 110 generally comprises a body having a substantiallysquare or rectangular cross-section. The connector 110 includes aplastic body 112 and one or more retention leads 140 extendingtherefrom. The body of the connector 110 is referred to as a plasticbody 112, however, other rigid or semi-rigid materials for the body 112are suitable. The plastic body 112 includes a top component surface 114,a bottom component surface 116, and side surfaces 118. Side surfaces 118include outer side surfaces 117, and also interior side surfaces whichare adjacent to a lead 140.

[0017] At least one of the retention leads 140 extends down the side ofthe side surface 118 along a vertical segment 142. The retention leads140 further includes a horizontal segment 144 which couples with asurface of the substrate 102. The retention lead 140 is disposedadjacent to a lower corner portion 119, as further discussed below.

[0018] Disposed between the side component surface 118 and the bottomcomponent surface 116 is a lower corner portion 119, as shown in FIG. 2.It should be noted that the term “corner” does not require that portion119 is square or rectangular. Instead, lower corner portion 119 refersto a general location of the component 100. The lower corner portion119, in one embodiment, is recessed away from the bottom componentsurface 116 and/or the side component surfaces 118 to form a recessedportion 120. The recessed portion 120 allows for solder to naturallyflow around the leads 140. In one option, the recessed portion 120includes a surface 122 which is substantially planar and is at anoblique angle relative to the side component surfaces 118 and the bottomcomponent surface 116, and forms an open area 124 between the at leastone retention lead 140 and the surface 122, and the printed circuitboard 102.

[0019] The surface 112, in one option, forms a beveled surface whichdefines the recessed portion 120. In another option, as shown in FIG. 3,the surface 122 is a rounded surface 123. The rounded surface 123 andthe lead 140 and the top surface 104 define an open area 125 whichallows for solder to flow freely between the retention lead 140 and thesurface 123, and the substrate 102. In yet another option, the lowercorner portion 119 forms a non-square surface to define a recessedportion 120.

[0020] To mechanically and electrically couple the component 100 withthe substrate 102, the substrate 102 is reflowed, for example, withsolder. It should be noted, however, that other coupling methods andmaterials are suitable. The soldering process allows for a fillet 170 ofcoupling material, i.e. solder, to couple the retention lead with thesubstrate 102, and to fill between the lower corner portion 119 and thefirst top surface 104 of the substrate 102. The recessed portion 120allows for the coupling material to freely flow therein, and to form amuch more substantial fillet, and forms a fillet with significantlygreater tensile strength. In one option, the fillet 170 has a firstprofile 172 which substantially corresponds to a second profile 113 ofthe surface 122 forming the recessed portion 120.

[0021] As mentioned above, the component 100 is coupled with thesubstrate 102. The component 100 includes surface mount components, andfurther includes the various embodiments discussed above and below. Thebottom surface 116 of the component 100 is disposed adjacent to thefirst top surface 104 of the substrate 102. In another embodiment, asshown in FIGS. 4A and 4B, the component 100 includes one or more pegs180, for example on the bottom component surface 116. The one or morepegs 180 extend away from the component 100 to a distal end 182, andassist in guiding the component 100 and in mechanically coupling thecomponent 100 with the substrate 102.

[0022] To couple the component 100 with the substrate 102, the distalend 182 of the one or more pegs 180 are disposed within the mountingholes 108 of the substrate 102. The one or more pegs 180 are sized to befreely received within the mounting holes 108. In another option, theone or more pegs 180 are sized to be received within the mounting holes108 with a friction fit. In one option, the distal end 182 of the one ormore pegs 180 is disposed within the mounting holes 108 such that thedistal end 182 is substantially even with the second lower surface 106of the substrate 102, where the distal end 182 does not protrude outfrom the second lower surface 106 of the substrate 102. In anotheroption, as shown in FIGS. 5A and 5B, the distal end 182 is disposedthrough the mounting holes 108 such that the distal end 182 ispositioned between the first upper surface 104 and the second lowersurface 106 of the substrate 102. By modifying the length of the one ormore pegs 180, the one or more pegs 180 assist in preventing exertion oftensile stress on the solder joints of the retention leads 140 (FIG. 3),for example, when the substrate 102 is placed on a flat surface, i.e. atable during testing.

[0023] A method for attaching the surface mount component to a substrateis shown in block diagram in FIG. 6. The surface mount componentincludes, but is not limited to, the various embodiments describedabove. In one embodiment, the method includes providing a component forplacement on a substrate, the component defined in part by a topcomponent surface, side surfaces and a bottom component surface, theside surfaces and the bottom component surface defining a lower portiontherebetween. The method further includes recessing the lower portionaway from the bottom surface of the component, placing the bottomcomponent surface adjacent to a first top surface of the substrate, andcoupling the component to a substrate, including forming a filletbetween a first top surface of the substrate and the lower portion ofthe component. In another option, the method includes recessing aportion of the component body adjacent the retention leads away from theretention leads.

[0024] In one option, the component includes two or more leads extendingfrom a portion of the component, for example, the side surfaces of thecomponent. The leads include a vertical segment and a horizontalsegment, where the horizontal segment is used to attach the component tothe substrate. The method optionally includes forming the fillet higherthan a horizontal segment of the lead, where the horizontal segment isin contact with the substrate.

[0025] In recessing at least a portion near the lead of the componentaway from the lead, optionally, a portion near the bottom surface of thecomponent is recessed, which allows for the solder to form around thelead in a natural profile. This provides a stress-free configurationthat is less susceptible to fracturing. This can be done in a number ofmanners. For instance, the recessed portion includes a non-squaresurface on the lower portion of the component. In another option, therecessed portion includes a beveled surface on the lower portion of thecomponent. In yet another option, the recessed portion includes arounded surface on the lower portion of the component. Since the sharpcorner of the component body has been recessed, this allows for betterdistribution of the solder with respect to the component body. Forinstance, the component body has a body profile which corresponds to therecessed portion. After the fillet of coupling material, for examplesolder, has been formed, the fillet material has a fillet profile formedbetween the lead and the lower portion of the component, where thefillet profile substantially corresponds to the body profile. The stressis distributed over a broader region, which renders the fillet to beless prone to fracturing.

[0026] Several other options for the method are as follows. Forinstance, the surface mount component optionally includes additionalmounting features, and the method includes disposing the mountingfeatures through mounting holes of the substrate, and in a furtheroption, disposing the mounting features through the mounting holes suchthat a distal end of the mounting features are substantially flush withthe bottom surface of the substrate. In another option, the methodincludes placing the distal end of the mounting features between thebottom surface and the top surface of the component.

[0027] The above described embodiments assist in retention of componentsto substrates, and further reduce failure of the components as a resultof force placed on the components during testing, shipping, and/orhandling, and user applications, where the user exerts both in-planeshearing and out-of-plane tensile stresses on the connector. It has beendetermined that the above described embodiments substantially improvethe tensile strength of RJ45 connectors including a modified componentbody. For instance, the connectors have a 100% improvement in tensilestrength over devices such as that shown in FIG. 1, when the connectorsinclude a modified component body, such as the connectors shown in FIG.2 or FIG. 3.

[0028] Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement which is calculated to achieve the same purpose maybe substituted for the specific embodiment shown. This application isintended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

What is claimed is:
 1. An apparatus comprising: a substrate having afirst top surface and a second lower surface, the substrate including atleast one mounting hole disposed through the first top surface and thesecond lower surface; a component coupled with the first top surface ofthe substrate, the component including a top surface, side surfaces anda bottom surface, the bottom surface disposed adjacent to the first topsurface; one or more pegs extending from the component to a distal end,the one or more pegs disposed within the mounting hole, the distal endof the peg disposed within the substrate without extending past thesecond lower surface.
 2. The apparatus as recited in claim 1, whereinthe component includes an upper portion and a lower corner portion, thelower corner portion is recessed away from the bottom surface and/or theside surfaces of the component.
 3. The apparatus as recited in claim 2,wherein the component is coupled with the substrate with a fillet ofcoupling material, and the fillet substantially fills a recessed areadefined in part by the lower corner portion of the component.
 4. Theapparatus as recited in claim 2, wherein the lower corner portionincludes a beveled surface defining a recessed area.
 5. The apparatus asrecited in claim 1, wherein the lower corner portion includes a roundedsurface defining a recessed area.
 6. The apparatus as recited in claim1, wherein the lower corner portion includes a non-square surfacedefining a recessed area.
 7. The apparatus as recited in claim 1,wherein the component comprises an RJ-45 connector.
 8. An apparatuscomprising: a substrate having a first top surface and a second lowersurface; a surface mount component coupled with the first top surface ofthe substrate, the surface mount component defined in part by a topcomponent surface, side surfaces and a bottom component surface; thebottom component surface disposed adjacent to the first top surface, theside surfaces and the bottom component surface defining a lower cornerportion therebetween, the lower corner portion recessed away from thebottom component surface and/or the side surfaces; a fillet of couplingmaterial disposed between the lower portion and the first top surface.9. The apparatus as recited in claim 8, wherein the lower corner portionhas a non-square profile.
 10. The apparatus as recited in claim 9,wherein a portion of the lower corner portion comprises a beveled edge.11. The apparatus as recited in claim 9, wherein at least a portion ofthe lower corner portion comprises a rounded surface.
 12. The apparatusas recited in claim 8, further comprising one or more pegs, the one ormore pegs disposed within a mounting hole of the substrate, the one ormore pegs extending away from the component to a distal end, the distalend of the peg disposed within the mounting hole, and the distal end ofthe peg does not extend past the second lower surface.
 13. The apparatusas recited in claim 8, further comprising two or more leads whichmechanically couple the surface mount component with the substrate, theleads extending between the side surfaces and the first top surface, thelower corner portion disposed directly adjacent to the two or moreleads.
 14. The apparatus as recited in claim 13, wherein the leadsinclude at least a first portion extending from the surface mountcomponent, the leads include a second portion which couples with the topsurface of the substrate, and the fillet extends higher than the secondportion of the leads.
 15. The apparatus as recited in claim 8, whereinthe substrate comprises a printed circuit board, and the componentcomprises an RJ-45 connector.
 16. A method comprising: providing acomponent for placement on a substrate, the component defined in part bya top component surface, side surfaces and a bottom component surface,the side surfaces and the bottom component surface defining a lowercorner portion therebetween; recessing the lower corner portion awayfrom the bottom surface of the component; placing the bottom componentsurface adjacent to a first top surface of the substrate; and couplingthe component to a substrate, including forming a fillet of couplingmaterial between a first top surface of the substrate and the lowercorner portion of the component.
 17. The method as recited in claim 16,wherein component includes a component lead, and the component leadincludes at least a horizontal segment which couples with the substrate,and the method includes forming the fillet higher than the horizontalsegment of the component lead.
 18. The method as recited in claim 16,further comprising forming a non-square surface on the lower cornerportion of the component.
 19. The method as recited in claim 16, furthercomprising forming a beveled surface on the lower corner portion of thecomponent.
 20. The method as recited in claim 16, further comprisingforming a rounded surface on the lower corner portion of the component.21. The method as recited in claim 16, further comprising including pegswith the component where the pegs extend to a distal end, and disposingthe pegs within mounting holes of the substrate, where the distal enddoes not extend past a bottom surface of the substrate.
 22. The methodas recited in claim 21, wherein disposing the mounting features with themounting holes includes placing the distal end substantially flush withthe bottom surface of the substrate.
 23. The method as recited in claim21, wherein disposing the pegs within the mounting holes includesplacing the distal end between the bottom surface and the first topsurface of the substrate.
 24. The method as recited in claim 16, whereinforming the fillet of coupling material includes forming a fillet havinga profile between a lead and the lower portion, and the profilecorresponds with a lower portion profile.
 25. An apparatus comprising: asurface mount component including a body; one or more leads coupled withthe body of the surface mount component; the one or more leads and thebody having a portion therebetween, where the portion is recessed awayfrom the leads to form a recessed area allowing solder to reflownaturally and stress-free therein.
 26. The apparatus as recited in claim25, wherein the portion includes a beveled surface defining the recessedarea.
 27. The apparatus as recited in claim 25, wherein the portionincludes a rounded surface defining the recessed area.
 28. The apparatusas recited in claim 25, the surface mount component further comprisingone or more pegs extending away from the component to a distal end, thedistal end of the peg sized to be disposed within a mounting hole of asubstrate.